PowerPoint Presentation

KURSUS ASAS REKABENTUK SISTEM PAM PENGAIRAN PERTANIAN

24 26 FEBRUARI 2015

IPMI UTARA

ASAS REKABENTUK PAM

Pengenalan Kepada Sistem Pengairan Pertanian

Penentuan Kadar Alir ( Flow)

Penentuan Kehilangan Turus (Head Loss)

Pengiraan Sistem Curve

Match System And Pump Curves

Select Pump Curves

Size Infrastructures

Determine Electrical Systems Control

Aksesori

WHAT IS IRRIGATION?

Application of water to soil by providing it to crop filled land.

To assist in crop production.

Sustain plant life.

Protecting crops from frost.

Goal: To make land fertile and lush.

Focus : Profitability energy optimization and better use of water resources.

FLOOD IRRIGATION

Half of the water applied to the field actually irrigates the crops and the other half is lost through evaporation, runoff, transpiration, weeds, and infiltration of uncultivated areas.

The efficiency of flood irrigation is not very high.

Important concerns :

Distribution uniformity.

Field flooding

Environmental impact of crops.

FLOOD IRRIGATION

Furrow Irrigation

Water is directed or pumped into a number of furrows, which are then flooded.

Gravity flow channel.

Requires lot of water.

Common irrigation techniques in tropical area.

MODERN PRESSURISED IRRIGATION

SPRINKEL IRRIGATION

Artificial Rain

Uniform application.

Two common types:

Fixed sprinkler

Travelling sprinkler

DRIP IRRIGATION

Water and nutrients are applied directly to the root zone.

Eg: Hydrophonics

Lot of maintenance clogging.

IRRIGATION PUMP

CRUCIAL CRITERIA

Availability of water

Type of water

Volume of water

Crops need for water

Source of Water

Common preception of water - Water was an infinite resource.

Water resources need to be managed.

Surface water drawn from rivers, canals, lake or reservoir.

Different source of water different type of pumps been used.

SOURCE OF WATER

Water availability on earth:

3% is fresh or 1% available for use

70% is held in the ice caps

30% is available as groundwater of from lakes and streams.

GROUNDWATER

PROS:

Most reliable water source on earth

Correct management is vital

Groundwater measurement are fairly complicated, because its flow is hidden.

CONS:

Supply limitations

Pump wear

Clogging

Over pumping

SURFACE WATER

2nd most common source of fresh water.

The most common source in Malaysias Irrigation activity.

Correct pump levelling / water storage.

Enemy of pumps for surface water:

Mud, silt, organism growth, woods, sand.

RAINWATER

Water source for raining season.

Pumping schedule will stop at this time.

PUMPS SELECTION

CRUCIAL CRITERIA

Typically been over-sized

Power consumption low

Maintaining system pressure

Adding variable speed control

Motor protection

DEFINISI PAM

JENIS PAM

PUMPS

DISPLACEMENTS

DYNAMICS

CENTRIFUGAL

AXIAL FLOW

MIXED FLOW, RADIAL FLOW

PERIPHERAL

SPECIAL EFFECT

JET

GAS LIFT

HYDRAULIC RAM

ELECTROMAGNATIC

RECIPROCATING

ROTARY

SINGLE ROTOR

MULTIPLE ROTOR

PISTON, PLUNGER

DIAPHRAGM

PD VS CENTRIFUGAL

Flow rate versus pressure

By looking at the performance chart, the centrifugal has varying flow depending on pressure or head, whereas the PD pump has more or less constant flow regardless of pressure.

PD VS CENTRIFUGAL

PD VS CENTRIFUGAL

Flow rate versus viscosity

The centrifugal pump loses flow as the viscosity goes up but the PD pumps flow actually increases. This is because the higher viscosity liquids fill the clearances of the pump causing a higher volumetric efficiency.

PD VS CENTRIFUGAL

Efficiency vs Viscosity

Viscosity also plays an important role in mechanical efficiency. Because the centrifugal pump operates at motor spefficiency goes down as viscosity increases due to increased frictional losses within the pump.

CENTRIFUGAL PUMP

Pam yang paling banyak digunakan di JPS.

3 jenis yang biasa digunakan Radial Flow, Axial Flow dan Mix Flow.

CENTRIFUGAL PUMP

Tapak

Penentuan Kadar Alir

Pam

Pengiraan Sistem Curve

Finallize

Saiz Infrastruktur

Pengiraan Kehilangan Turus (Head Loss Calculation)

Matching system and pump curve

Pemilihan Pam

Sistem Kawalan Elektrik

Aksesori

PROSES REKABENTUK SISTEM PAM PENGAIRAN

Penentuan Kadar Alir

Pengiraan Kehilangan Turus (Head Loss Calculation)

Pengiraan Sistem Curve

Sistem Curve

Range Curve

Head, Power Consumption, NPSH Curve

Adverse Hydraulic Phenomena

Excessive pre-swirl

Change flow conditions

Change in pump performance

Bearing wear

Cavitation across impeller

Uneven velocity distribution

Entrained air

Minor air entrainment will lead to a clear reduction in pump performance and loss of efficiency; the severity depends upon the quantity of air entrained and the pump type.

Vortices

Unlike excessive pre-swirl, vortices appear locally with higher intensity and are a major hindrance to proper pump operation, resulting in cavitation, uneven load, noise and vibration. There are several different types of vortices. The most commonly known type is the free surface vortex, which can have varying degrees of intensity from weak surface vortices to fully developed vortices with a continuous air core that extends from the surface into the pump. Less well known, but just as common is the vortex that originates under the surface from the sump bottom, walls or between two pumps, and extends to the pump inlet. This type of vortex can achieve high rotational speeds with high subpressures and cavitations.